Facilitating high waxy oil transportation, the decrease in oil viscosity and the increase in the pipeline transmission capacity remain in the spotlight of researchers.In the situation when development of some Ukrainian oil fields has either been suspended or even ceased to exist due to the russian aggression, investigation of oils, which are produced in the western region of Ukraine and are primarily high waxy and high-viscosity oils, is of particular importance.The analysis of recent studies shows that despite a variety of publications regarding transportation problems of high waxy oil, investigations of rheological behavior of oils from the western region of Ukraine in the presence of depressants actually have not been studied.The effect of depressants on rheological properties of high waxy oil is individual, and therefore, to ensure maximum efficiency of oil transportation, it is necessary to experimentally determine rheological parameters for each specific case, adhering to corresponding operating conditions.This article aims to study the effect of Dodiflow 5236 industrial depressant (Clariant, Switzerland) on rheological prop-erties of Dolyna and Borislav oils from the western region of Ukraine.In this work, rheological parameters of Dolyna and Boryslav oils without depressant and in its presence were determined. Using the Rheomat-30 rotational viscometer, the dynamic viscosity and shear stress were determined. It was found that adding 1000 ppm of Dodiflow 5236 decreases the dynamic viscosity by 6 times for Dolyna oil and by 7 times for Boryslav oil. At the same time, the initial shear stress is decreased by almost the same amount, by 6 times for Dolyna oil and by 6,5 times for Boryslav oil.Determining the unique properties of oils from the western region of Ukraine and their interactions with depressants are important for developing the strategy of oil storage and transportation to avoid negative impact on the product quality and efficiency of its use. The obtained results regarding improvement of rheological properties of Dolyna and Boryslav oils when following the depressant introduction technology will allow ensuring optimal efficiency and avoiding many problems in the oil transportation system.

Для покращення транспортабельних властивостей високопарафінистих нафт Долинського і Бориславського ро-довищ досліджено їхні реологічні властивості у разі додавання промислового депресора Dodiflow 5236 (фірма Clariant, Швейцарія). За допомогою ротаційного віскозиметра визначено динамічну в’язкість і напруження зсуву чистих нафт і нафт з депресорами. Встановлено, що додавання Dodiflow 5236 покращує реологічні властивості досліджуваних високопарафінистих нафт. Їхня динамічна в’язкість зменшується в 6-7 разів, а напруження зсуву – у 6-6,5 раза.